It is known that the heat storage capacity of textile fibers and shaped articles can be increased if the shaping polymer is combined with an organic phase change material which can exchange energy with the surrounding area through melting/solidification transition, conformational transition or deorientation/crystallization. The extent of the energy exchange and the effective temperature range correlate with the chemical structure, the change in physical enthalpy and the concentration of the phase change material. It is primarily decisive that the energy exchange effect in the fiber is retained as the result of the molecular near-orientation of the phase change material in or on the shaped article. The following solutions are known:
Firstly, phase change materials are encapsulated with an organic polymer layer and then the capsules are incorporated into a polymer fiber or applied to a fabric (e.g. EP 1 658 395=US 2006/0279017). Micro-encapsulated phase change materials are also used in the examples according to WO 2005/017247 in the production of cellulose fibers having thermoregulatory properties by the Lyocell process. It has proven disadvantageous here that the encapsulation of the phase change material takes place separately from the shaping, or from the processing. Inevitably, a compromise between available capsule batches as regards material and suitability for the shaping process is necessary. In the case of dry-wet extrusion processes, requirements such as fineness and particle size distribution, mechanical and chemical stability, suitability of the phase change material for the field of use, availability and cost, inter alia, are placed on microcapsules.
Furthermore, phase change materials can be incorporated into a polyolefin matrix or a polymer suspension. For example, the production of melt-spun polyolefin fibers which comprise phase change materials having a melting point from 15 to 65° C. is known (U.S. Pat. No. 5,885,475).
The direct incorporation of a phase change material (e.g. a polyethylene glycol) into a hollow fiber is described in U.S. Pat. No. 4,908,238. Here, however, stabilization of the phase change material in the shaped article was dispensed with. From the point of view of the structure, it resembles a microsandwich construction. Simple sandwich structures are disclosed e.g. in US 2003/124278.
According to one particular embodiment in WO 03/027365 (=EP 1 430 169), it should be possible to mix in the PCM during the production of a cellulose fiber in raw form. However, here, no permanent bonding of the PCM to the matrix material (cellulose) can arise, and it is also not possible to spin a fiber from a mixture of PCM and dissolved cellulose.
There is interest in releasing active ingredients from a woven or a cellulose fiber. It is also known to anchor encapsulated, active-ingredient-containing material to the surface of fibers (WO 01/73188) or to incorporate them therein (WO 2006/066291). The possibility of producing fragrances and active ingredients as microcapsules is described e.g. in EP 1 243 326. Again, as a result of the limited availability, the microcapsule has proven to be disadvantageous for industrial application since the encapsulation takes place separately from the shaping.
No approaches are known from the literature as to how the generation of permanent nonpolar organic micro-inclusions into a hydrophilic network-forming polymer, such as cellulose, can be realized by adding the raw materials (solvent, cellulose, nonpolar organic compounds and mixtures, thickeners and phase promoters) to the spinning solution and subsequent shaping in one process. Hitherto, it has also not been described that organic compounds which may be dissolved or suspended in the nonpolar organic compounds and mixtures can be used as modifiers (change in the melting range of phase change materials by e.g. lowering the melting point) or releaseable active ingredients if they were to be incorporated as permanent, nonpolar organic micro-inclusions into a hydrophilic network-forming polymer, such as cellulose.
Only the incorporation of nanoscale active ingredients in powder form and/or of carbon nanotubes was known (WO 2004/081267). Teaching with regard to the incorporation of lipophilic substances into a polar cellulose solution cannot be inferred therefrom.
Proceeding from prior art as described in WO 2006/066291, the object of the invention was accordingly to develop a direct process for producing cellulosic shaped articles with inclusions of nonpolar organic compounds and mixtures utilizing the direct incorporation of these organic, nonpolar compounds and mixtures. If appropriate, these cellulosic shaped articles with inclusions of nonpolar organic compounds should be equipped with further functional additives which are concentrated particularly at or close to the surface of the inclusions.
Moreover, it is within the scope of the object to develop a process in which active ingredients can be dissolved and/or stored in cellulosic shaped articles and can be released to the surrounding area in a controlled manner over a prolonged period.